Wednesday, September 30, 2015

Wood Stork

Wood Storks are conspicuous waders of the Southeast. Their populations have suffered from water mismanagement in the Everglades, but numbers have increased in northern Florida, South Carolina and Georgia (Coulter et al. 1995). The species also breeds from Mexico through northern South America.

In the Everglades National Park, where, in April, Erika and I took these photographs, Wood Storks soar in thermals, often to heights over 3000 feet. They then glide as far as 30 miles to feeding areas. Birds return in the same fashion to their nesting colonies, occasionally waiting for the next day’s thermals to develop. Birds descend from the thermals either with long, downward, circular glides (like the bird in these photos) or in steep, high-speed dives (Coulter et al. 1995).

Tuesday, September 29, 2015

Eastern Kingbird

I have posted before that, when we were in the Amazon Jungle in Ecuador,  Erika and I often saw large flocks of Eastern Kingbirds. Apparently the flocks are maintained until after the birds migrate into North America. Last May, John Holden and I found about a dozen Eastern Kingbirds along the Wells Lake causeway in southern Rice County. Curiously, in South America, these kingbirds eat fruit, whereas here they rely on flying insects (Murphy 1996).

One of these days I will succeed in photographing a male kingbird’s scarlet crown.  Looks like I came close with this bird. Meanwhile, compare this photo with that of the Gray Kingbird. Note the much larger size of the Gray Kingbird’s bill.

Sunday, September 27, 2015

Gray Kingbird

After leaving Long Key, we proceeded to Duck Key, which looked like a gated community. On our own, we probably would not have entered—but the BirdsEye bird-finding app assured us that Gray Kingbirds had recently been reported on Duck Key. After driving though the residential streets, I opened the window and heard the raspy call of the kingbird.  “Sounds like it is coming from behind that house!” I called, as we turned a corner. And there was our kingbird. I took some distant photos. A few blocks distant, another Gray Kingbird obligingly forayed from its telephone-line perch.

Gray Kingbirds breed throughout the West Indies, northern South America, and the coastal southeastern United States, from Florida north to South Carolina and Mississippi. These flycatchers consume large flying insects, including beetles, dragonflies, bees, and, as you as see in the bottom photograph, wasps.  They also eat lizards and various fruits (Smith and Jackson 2002). Gray Kingbirds look superficially similar to Eastern Kingbirds, but are more gray overall, lack the broad white terminal tail bands, and have more robust bills. I suspect the size of the bills protects the kingbirds from venomous insect stings.

Saturday, September 26, 2015

Black-throated Blue Warbler 2

On Thursday I posted an account of our seeing a male Black-throated Blue Warbler on Long Key last April. The same evening, I banded a female here in Northfield, Minnesota. You may recall that I wrote that ornithologists did not believe initially that the sexes belonged to the same species. This female is identified by her olive coloration and small, white, wing spots.

Black-throated Blue Warblers breed in the arrowhead of Minnesota and mainly migrate on the East Coast of the United States. Thus southeastern Minnesota is on the periphery of their migratory range. I also listed about two-dozen Black-throated Blues in eastern South Dakota. One might hypothesize that these birds are heading for the western-most wintering grounds in the Yucatan, Belize and Honduras. It would be great to get a recovery of one of these banded birds. Nevertheless, eBird maps show many records from the western United States.

Friday, September 25, 2015

Audubon’s Warbler in Minnesota

On Thursday, 24 September 2015, at my home (in Northfield, Rice County, Minnesota), a Yellow-rumped Warbler caught my eye in my banding net. The throat and belly were yellowish. The throat color did not wrap around the auricular feathers (ear patches). The wing bars were relatively wide. Finally, the eye-strip is very faint. I believe this bird is a young Audubon’s Warbler, the western race of the Yellow-rumped. Last spring, you may recall, I banded a bird I thought to be a hybrid between the two races. As I mentioned in that previous post, about a half dozen Audubon Warbler records exist from Minnesota.

Thursday, September 24, 2015

Broad-winged Hawk

Erika and I observed two flocks of five Broad-winged Hawks on Wednesday, 23 September 2015. The first flock flew over Northfield in Rice County; the second flew over the nearby Carleton College arboretum in Dakota County. They could have been the same birds (although the second flock was about a mile north of the first). These hawks often migrate in flocks of up to thousands of individuals. Only rarely does one notice single migrants.

This photo of a juvenal bird is of one of the arboretum flock. Adults show a striking black and white banded tail.  In most studies, small mammals. birds and amphibians are their main prey. They are generalized predators, and take a wide variety of prey items. To me, it looked like the arboretum birds might be feeding on flying dragonflies. Although these hawks are known to take insects like grasshoppers, Gooddrich et al. (2014), in The Birds of North America, do not mention dragonflies.

Wednesday, September 23, 2015

Great Pondhawk

Having failed to find Gray Kingbirds at Sanibel, we searched for these flycatchers on 2 April in Long Key State Park in one of the northern Florida Keys. According to the BirdsEye bird-finding app, Gray Kingbirds had recently been seen at the park; and reports of a Key West Quail-Dove gave us added incentive to visit. Other birders searched with us, but we saw neither bird—the park was just too big.

But I did come face-to-face with a Great Pondhawk. I had Great Pondhawks on the brain since entering Florida, but, until now, all the pondhawks I encountered proved to be Easterns. I knew the dragonfly I desired had green stimata, the small spots often found near the tips of odonate wings. When I saw this individual, I immediately knew its identity. The species is found in southern Florida and throughout the West Indies and from Oklahoma south to Argentina.

Tuesday, September 22, 2015

Black-throated Blue Warbler

Erika and I left Sanibel Island on 1 April and drove across the peninsula and spent two days in Florida City. Our BirdsEye bird-finding app, indicated that Gray Kingbirds, which we missed in Sanibel, had been seen at Long Key State Park, along with a rarer bird, the Key West Quail-Dove.

We arrived at Long Key on 2 April and were greeted by this Black-throated Blue Warbler. Males and females look so different that early ornithologists thought that they were different species. Males, like this one, do not molt into a cryptic fall plumage, and, thus, are easily identified all year. I have posted a photo of a female elsewhere in this blog.

Minnesota is about as far west as Black-throated Blue Warblers breed. They winter in forests in the Greater Antilles, the Yucatan, and Belize. Most migrate along our Atlantic Coast. We assume the bird in the photo is an early migrant in south Florida. Populations of this warbler have declined due to deforestation, both in their breeding and wintering grounds. Only as fallow fields have recently reverted to forest have numbers rebounded (Holmes et al. 2005).

Monday, September 21, 2015

Bottle-nosed Dolphin

Despite the hoards of people and relatively high cost of accommodations, we enjoyed our week in Sanibel Island during the last week of March. The birds, shells, dragonflies and beach combing all conspired to make the week fly by.

I suspect this is a Bottle-nosed Dolphin, which entertained the beach-goers, young and old. “I wonder how you tell that from a shark?” asked a man next to me. “No blood in the water,” I replied. Maybe not so funny, considering the shark attacks to come the following summer along Florida’s Atlantic coast. Sharks, of course, do not breathe air through a blow-hole and their hind fins ride up and down rather than flat in the water.

Sunday, September 20, 2015

Gopher Tortoise

The Sanibel Island Lighthouse and Beach Access are at the eastern edge of the island. The area is a wildlife refuge and is so popular that parking often is a problem. We visited twice towards the end of our stay at the end of March and saw interesting birds and a hoard of birders. Several interesting warblers were in the vicinity, but light was generally too poor for good photos. The crowd of noisy birders also blemished the experience.

We did see Gopher Tortoises, which are threatened in their southeastern range by predation, habitat destruction, and hunting. People have eaten tortoises through the ages. During the Great Depression they were known as “Hoover Chicken." Today tortoises are often hunted illegally. Until 1989, when Florida banned the practice, Gopher Tortoises were captured for turtle races. Tortoises are also kept as pets. Captive turtles are susceptible to a variety of pathogens.

On Sanibel Island, Gopher Tortoises are found in most upland areas, but mostly on conservation lands. Statewide, the species is classified as Threatened (MySanibel.com). They are herbvores that consume a wide variety of plants. Many other animals depend on tortoise burrows, and the turtles are thus considered to be a keystone species in their ecosystems.

    Saturday, September 19, 2015

    Franklin's Gull

    The bird above is an adult, non-breeding Franklin’s Gull.  In the lower photo, note the brownish upper wings, typical of a first-winter-plumaged bird. John Holden and I took both these photos on the paved road on the east shore of nearby Circle Lake.

    These gulls breed in the Canadian Prairie Provinces and sporadically across the Upper Midwest and western United States. Only a few breeding colonies are known from Minnesota. Across their range, breeding colonies are scattered, and not used every year. In any given year, only about 50 active colonies may exist. Perhaps more remarkably, almost all Franklin’s Gulls winter off the coasts of Peru and Chile.

    This history of this bird’s name, Larus pipixcan, is interesting. The gull was first collected in 1823 by John Richardson on the first Franklin expedition to northwestern Canada. The specimen was first misidentified as Laughing Gull. After Franklin’s second expedition, Richardson recognized that this species was new, and named it Franklin’s Rosy Gull, Larus franklinii. Although Richardson wrote a paper describing the new gull in 1830, his work was not published until 1832. Meanwhile, JohannnWagler, a German herpetologist, described a Franklin’s Gull from Mexico, publishing his work in 1831. Wagler’s name for the bird, Larus pipixcan, therefore has priority over Richardson’s. Pipixcan is an Aztec word that refers of Mexico, a region where Franklin’s gulls are only transient. My sources for this account include Burger and Gochfeld (2009) and Gruson (1972).

    Thursday, September 17, 2015

    Green Iguana

    I have previously blogged about Green Iguanas. They seem like they would make great pets, and every year some 8000 are imported into the United States from Central and South America. But pet owners often become frustrated—these lizards require special lighting, space, and diets. They are herbivores, but do poorly on a diet of iceberg lettuce, and require precise nutrient ratios. A carnivorous diet may cause renal failure. Young iguanas may need to consume their parents’ feces to acquire essential micro-organisms. The result is that many pet iguanas are set free (or escape) resulting in damage to native vegetation—the species is known to consume nearly 100 different kinds of plants (Wikipedia).

    Erika and I were amazed by this Green Iguana on Sanibel Island last March. While we watched, the reptile changed from dull gray to bright green.

    Wednesday, September 16, 2015

    Swallows

    With the fall season, Barn Swallows begin to head south, often join mixed swallow species flocks. On 9 September, at the 180th Street Marsh in nearby Dakota County, John Holden and I counted 26 Barn Swallows, although probably quite a few additional individuals escaped our tally. Among the Barn Swallows were a few Cliff Swallows, one Tree Swallow, and two Purple Martins, one of which can be seen in the lower photo. Martins are common enough, but I do not see many away from their nesting boxes. They are known to congregate in some areas and may make fairly direct migrations from those sites. On the other hand, eBird only shows eight Minnesota records from this September.

    Barn Swallows often roost in flocks of hundreds in marshes. During migration, Barn Swallows cover from 2 to 194 kilometers per day, with greater distances covered as the fall progresses. They are trans-Gulf of Mexico and trans-Caribbean migrants. A Barn Swallow banded in New York was recovered 44 days later off Panama, which is an average of about 89 kilometers per day (Brown and Brown 1999). Although a few stragglers have been recorded in the United States during the winter, most North American Barn Swallows winter in South America.

    Tuesday, September 15, 2015

    Sanderling

    Sanderlings breed around the high Arctic around the world and winter along most of the planet's temperate and tropical beaches. Numbers at any given locations, however, are usually relatively small, compared with many other sandpipers. Sanderlings are often identified by their habit of running before and after waves on their beaches. Sometimes wintering males or females are highly territorial, but usually both sexes occur together in conspecific, non-territorial flocks (Macwhirter et al. 2002).

    Erika and I found this Sanderling flock along the Sanibel Island beach on 24 March 2015. I have previously blogged on the species.

    Sunday, September 13, 2015

    Green-eyed Robberfly

    This fantastical creature flew up and landed on the path in front of Erika and me as we hiked in the Carleton College arboretum prairie. At first we thought it was a monster dragonfly, but the wings did not lie correctly for a dragonfly. Googling “green-eyed fly” quickly landed identification as a Robber Fly, one of the “largest and most abundant families of present day insects" (Robber Fly Website). Over 7000 species are known worldwide; I have previously blogged on Machimus notatus, another species of Robber Fly.

    Further search on the Internet came up with Wisconsin Butterflies. These flies are not butterflies and do not always have green eyes, but Green-eyed Robber Fly seems an appropriate name. The Wisconsin site just calls it a Robber Fly, Promachus vertebratus. This species is the most common Promachus in Wisconsin and, with its spotted abdomen, is relatively easy to identify. The species inhabits disturbed areas and old farmsteads. They fly from mid-July into early September. Robber Flies feed on other insects, mostly those that eat plants. Some species of Robber Flies can decimate apiaries. Other insects such as parasitic wasps and flies are also eaten.

    Saturday, September 12, 2015

    Hummingbird Wing

    My hummingbird feeder is at the edge of the woods. The feeder is infrequently and only briefly in the sun. On Thursday, when I saw this Ruby-throated Hummingbird, with its wings blurred and backlit in the sunlight, I ran for my camera.

    Researching the Internet gives you a lot of different numbers for how fast hummingbird wings beat. Wikipedia’s data seem similar to other sources—hovering, typical hummers flap their wings about 50 to 80 times per second. While hovering, the wings make a figure-8 pattern. Unlike large insects that generate lift equally with their up and down strokes, hummingbirds generate about 75% of their lift during the downstroke, and 25% on the upstroke. Furthermore, the downstroke uses less energy than does the upstroke.

    Friday, September 11, 2015

    Tricolored Heron

    Frederick (2013) writes that the Tricolored Heron suffered from the millinery slaughter of North American herons and egrets in the 1880s, but was a collateral victim as mixed colonies were destroyed. Populations have rebounded along with egrets and herons. Now populations are again declining as a result of coastal habitat destruction. Erika and I found this Tricolored Heron underneath the headquarters of the Ding Darling National Wildlife Refuge on Sanibel Island.

    Thursday, September 10, 2015

    Swallow-tailed Kite

    Erika and I were surprised by the numbers of Swallow-tailed Kites that we saw during March's Florida trip. This kite was one of several we saw at Sanibel Island.

    In almost ten years of birding in Louisiana, we never saw this raptor. Meyer (1995) suggests the relative ease of seeing this species in Florida masks its scarcity. It is easily seen in the few places it nests. Hundreds of kites, which gather from great distances, can been seen in communal roosting sites. In the 1880s, Swallow-tailed Kites were found from Minnesota and South Dakota across much of the eastern United States. Now they are restricted to swamps of the extreme southeast, from South Carolina to extreme eastern Texas.

    The species is occasionally reported in its previous range—in September 2007, in Mitchell, South Dakota, I saw one feasting on flocks of migrating dragonflies. Flying insects, in fact, make up most of this hawk’s diet. Only when breeding does it consume a variety of vertebrate prey—small frogs, lizards, birds and snakes, which are taken from treetops and swamp vegetation.

    Tuesday, September 8, 2015

    Scarlet Skimmer

    During one of our unsuccessful searches last March for the Gray Kingbird in the Ding Darling National Wildlife Refuge, I spied this red skimmer. Erika was some distance ahead of me, as is usual, due to my photographing miscellaneous birds and odes. “Better come back here and look at this one,” I called. “Gosh, that’s a beautiful dragonfly,” replied Erika.

    Scarlet Skimmers are North America’s only introduced odonate.  In the Lower 48 States, they are only found in south Florida. They are native and widespread in southern Asia, from the Middle East to China and Japan, through the Philippines and northern Australia. The species was first discovered in Florida in the 1970s, and has since been found in Cuba, Jamaica, Hispaniola. Puerto Rico, and Hawaii. I do not know who introduced them to the New World, nor do I know why. The larvae, however, are eaten in parts of China (Wikipedia). BugGuide.com, however, claims the introductions were accidental.

    Monday, September 7, 2015

    Striped Mud Turtle

    I believe this creature that I photographed last March in the Bailey Tract of the Ding Darling National Wildlife Refuge is a Striped Mud Turtle. The yellow head stripes are just barely visible. The species is found throughout most of Florida and up the Atlantic coastal plain to southeastern Virginia. These turtles inhabit swamps and canals. Striped Mud Turtles are odd in that the females nest in the fall, unlike other species that breed in the spring or summer (Savannah River Ecology Lab).

    I was surprised as I worked on this photo for presentation for my blog. Do you see the damselfly on the turtle’s back? I never saw the damsel when I took the photograph. Greatly enlarging the photo does not give a definite identification, but the damsel may well be an Eastern Forktail.

    Sunday, September 6, 2015

    Wood Thrush

    Among four Swainson’s Thrushes I banded Friday evening, I was surprised to find a Wood Thrush. This thrush is common enough in area woodlands, but I do not catch many in the small forest behind our home. Our forest patch must be too small to support resident Wood Thrushes. This young bird must be a migrant—unfortunately, in our woods, I do not hear the loud, flute-like calls during the breeding season.

    Because Wood Thrushes are intolerant to forest fragmentation, both in their eastern North American breeding territory and in their Central American wintering range. they have become increasingly uncommon since the 1970s (Evans et al. 2011). Habitat destruction in North America leaves this species vulnerable to nest parasitism by cowbirds and, in both North and South America, cutting of forests forces Wood Thrushes into secondary habitats where they become more exposed to various predators.

    Saturday, September 5, 2015

    Florida Cooter

    In the Bailey Tract of the Ding Darling National Wildlife Refuge, Erika and I found two turtles basking in the sun. I believe they are Florida Cooters, which are known to be social turtles, often basking in groups (Savannah River Ecology lab). The species is found throughout the southeastern coastal plain, from Mississippi to Virginia. Three races across this range may, in fact, be distinct species. In any event, they are omnivorous. Females prefer aquatic plants, while males prefer aquatic invertebrates.

    Thursday, September 3, 2015

    Willet

    Three Willets loafing on the Sanibel Island beach last March—all three appear to be asleep, or at least they have their eyes closed. Nobody has quantified the daily time budgets of Willets —such a study might make a nice Master’s degree. Willets are known to roost at high tide and they rest communally when not breeding (Lowther et al 2001).

    Due to the advent of molecular genetics studies, these days avian systematics is in a state of flux. Willets, for example, used to reside in their own genus, Catoptrophorus, a Latinized version of the Greek for mirror-bearing—referring to the striking white wing stripes visible on flying Willets. Genetic research concludes that these birds are, in fact, members of the genus Tringa (along with Solitary Sandpipers and the yellowlegs).

    Wednesday, September 2, 2015

    Sandwich Tern

    Sandwich Terns are named after the town from which they were first described in 1987. They are found across much of Europe, the southeastern Atlantic coast and Gulf Coasts of the United States, and the Caribbean and Atlantic coasts of South America. Three races are recognized. Those found in Europe and North America are quite similar. South American birds have yellow bills and some ornithologists think that they are a distinct species—Cayenne Terns. North American birds were formerly known as Cabot’s Terns, but one does not see that name very often in modern literature.

    This Sandwich Tern gazed upon Erika and me along the Sanibel Island, Florida, beach last March. We also listed this species on our previous trip to the area in 2012.

    Tuesday, September 1, 2015

    Green Heron

    Fortunately, John Holden and I were wearing our hats when we spied this Green Heron in Rice County, Minnesota, last Wednesday. This little heron goes by many names, including “Shite-polk,” due to its habit of defecating as it flies from its perch.

    Green Herons have other names too, including Green-backed, Striated, and Little Green heron, due to ornithologists’ confusion about the species' systematics. This situation is not surprising. The birds’ range is huge—North and South America, Africa, and Asia. At least 33 races are recognized, and scientists argue that some are, in fact, distinct species. For example, Martinez-Vilalta et al. (2014) consider all these populations to be subsets of a single species, the Green-backed Heron. Davis and Kushlan (1994) follow the current American Ornithologists’ Union edict that the North American population is a distinct species, the Green Heron, distinct from South America’s Striated Heron. This unlikely conclusion leaves the South American birds more closely related to Old World populations than to North American birds.

    When Erika and I visited the Galapagos Islands, we saw Lava Herons, like the one in the photo below. This population looks like very dark Green Herons. These birds may be another species in the Green Heron complex. Most ornithologists, however, consider them to be a dark morph of the South American birds. They are variable in color—this one is a bit paler than most—and no significant genetic differences have been found between Galapagos and mainland Striated Herons.